The present invention relates to an image developing method and the related developer, and, more particularly to the image developing method for indicating developing progress and condition by means of color change of the image on metal base material, to help judging the correct developing time.
In color TV screen and photoresistive printing plate manufacturing and some other precision industries, the process in which light sensitive resin is coated on metal base material for duplicating image through exposure, developing and further etching and electroplating is now commonly applied in manufacturing some component parts.
Theoretically, in ideal developing the light sensitive coating in the area which is not required (nonimage area) is completely removed while the light sensitive coating in the area which is required (image area) is left intact. The light sensitive resins in the image area and nonimage area dissolve at different rates. Therefore, the best developing quality is achieved when the light sensitive resin in the nonimage area is completely dissolved and maximum amount of the light sensitive resin in the image area is maintained. Attempts have been made to solve the problems by adding siliceous sands or silicon dioxide into regular developer solution to increase the dissolving speed difference. However, this method can only slightly improve image enhancement.
When the film of light sensitive resin in the nonimage area is dissolved to an extent of 0.5VM left thereover, the film becomes transparent, and it is impossible to observe the results visually. Even if 0.1VM light sensitive resin is left over, developing quality will be too below. However, the right standard developing time is difficult to judge. Therefore, over developing is commonly used to remove the light sensitive resin from the nonimage area completely, so as to prevent under developing. But during removal of the nonimage area, it is difficult to completely above the nonimage area without the simultaneous removal of image area. Excessive over development will destroy developing quality and cause developing failure. Standard developing time required may vary with the quality, and the thickness of the light sensitive resin coated, the concentration of developing solution, the developing temperature and other factors. In consequence, correct developing is difficult to achieve.
A color indicator image developing method may solve the said problems, in which the developer solution is a developer solution added with or partially replaced by a kind of color change agent which acts to change metal surface color from 0-60 seconds (or the most preferably, from 0-10 seconds) after contact with the metal, or a kind of double-purpose developer solution which reacts to perform image developing process and make metal surface change color immediately (0-10 seconds) after the light sensitive resin in nonimage area is dissolved and the metal surface is exposed in the developer solution. Through color change, the standard developing time is identified. Even if light sensitive resin is partly dissolved due to uneven thickness of coating, the well developed area and the under developing area are obviously indicated through color change indication. Because the contact time of the color change agent and the base metal will affect the color of copper, therefore, resulted and failure resulted from over development or under developing can be eliminated through the present invention since the whole developing process through color change can be observed. Therefore, the standard developing time is instantly indicated. By means of the developing method, a satisfactory quality developing process to a precision image can be easily achieved.
Further, dark dye stuff is normally added to the light sensitive resin. The image area absorbs the dye stuff so as to increase the range of color contrast between the image and the base material. However, the use of dark dye stuff tends to interfere with the sensitivity and the strength of the film. Obvious color convert is presented on the metal surface of the nonimage area and color contrast between the nonimage area and the image area, checking the quality of image developed. Therefore, the present invention can also eliminate the troubles encountered in conventional developing methods which uses dark dye stuff additives.